A Jaws-for-grownups horror that excels on many levels. During Fourth of July celebrations at a small seaside resort, swimmers come out in rashes. These turn into blisters that give way to agony and disgusting death. The condition spreads, hospitals are overwhelmed, and the disease-control centre is baffled. It turns out that steroid-rich excrement dumped by a chicken farm has caused a fish parasite to mutate catastrophically. Victims' gloriously repulsive experiences include at least one all-time top-10 scare when the mini-beast (literally) jumps the species gap from fish to human. Yet there's much more than revulsion to this sidetrip into genre from Rain Man veteran Barry Levinson. The found-footage contrivance is rebooted to lay bare the multimedia evidence trail that we now leave behind us. Acute observation of human behaviour is accompanied by sharp writing and an affecting performance from newcomer Kether Donohue as a novice reporter out to penetrate the cover-up.